Exhaust gas outlet means for an internal combustion engine

ABSTRACT

Exhaust gas outlet means for an internal combustion engine comprising an exhaust pipe having an outlet end of a flattened cross-sectional configuration with a width smaller than diameter of unflattened portion and an open-ended fresh air suction pipe disposed with a clearance with the exhaust pipe and having a portion of reduced cross-sectional area around the outlet end of the exhaust pipe so as to define a suction throat in the vicinity of said outlet end.

United States Patent [191 Ohtani et a1.

[451 Dec. 31, 1974 EXHAUST GAS OUTLET MEANS FOR AN INTERNAL COMBUSTIONENGINE [75] Inventors: Toshio Ohtani; Takahiro Sato;

Fukishi Sumitomo, all of Hiroshima-ken, Japan [73] Assignee: Toyo KogyoCo., Ltd., Hiroshima-ken, Japan [22] Filed: Sept. 6, 1973 [21] Appl.No.: 394,817

[30] Foreign Application Priority Data Sept. 11, 1972 Japan 47-1063732,973,825 3/1961 Bertin 181/43 3,016,692 1/1962 Iapella et al.

3,033,494 5/1962 Tyler et a1.

3,043,097 7/1962 Inman et al 181/43 X FOREIGN PATENTS OR APPLICATIONS252,546 6/ 1926 Great Britain 181/43 521,435 3/1955 Italy 181/43 738,01412/1932 France 181/43 1,378,224 10/1964 France 1 181/43 770,689 9/1934France 60/319 804,440 11/1958 Great Britain 60/319 726,608 3/1955 GreatBritain 181/43 Primary Examiner-Richard B. Wilkinson AssistantExaminerVit W. Miska Attorney, Agent, or Firm-Fleit & Jacobson A [5 7]ABSTRACT Exhaust gas outlet means for an internal combustion enginecomprising an exhaust pipe having an outlet end of a flattenedcross-sectional configuration with a width smaller than diameter ofunflattened portion and an open-ended fresh air suction pipe disposedwith a clearance with the exhaust pipe and having a portion of reducedcross-sectional area around the outlet end of the exhaust pipe so as todefine a suction throat in the vicinity of said outlet end.

4 Claims, 7 Drawing Figures PATENTEU 9533 1 4 sum 10F 2 FIG.4

FIG.3

FIG.6

FIG.5

EXHAUST GAS OUTLET MEANS FOR AN INTERNAL COMBUSTION ENGINE The presentinvention relates to an engine exhaust system and more particularly toexhaust gas outlet means for an automobile engine exhaust system havingexhaust gas cleaning means.

Recently, in an automobile engine, it has been necessitated, in order toreduce air polluting constituents in the exhaust gas, to provide exhaustgas cleaning means such as a thermal reactor or a catalytic reactor inthe exhaust system of the engine. However, it has been noted that such atype of exhaust gas cleaning means cause an increase in temperature ofthe exhaust gas at the outlet end of the exhaust pipe and in some casesit has been found that the exhaust gas temperature is as high as 600C.Particularly, when an engine is operating at an idling speed with achoke device in operation, the reaction in the exhaust gas cleaningmeans is highly activated and the exhaust gas temperature is remarkablyincreased. The increased temperature of the exhaust gas causes varioustroubles such as a burn hazard of a person, a fire hazard and adverseeffects on the road surface.

l-Iithertofore, in addition to a conventional structure in which theexhaust pipe has a merely straightly cut outlet end, there has beenproposed to provide an openended fresh air suction pipe having a reducedinner diameter portion which is disposed with a clearance around theoutlet end of the exhaust pipe so that a throat portion is formedbetween the outlet end of the exhaust pipe and the reduced diameterportion of the suction pipe. An example of such an arrangement isdisclosed by Japanese Patent Publication No. 19042/69. This arrangementis found as being effective to a certain degree to reduce thetemperature of the exhaust gas, however, it cannot reduce thetemperature to a satisfactory level. Further, it has also been proposedto open the outlet end of the exhaust pipe downwardly so that theexhaust gas is discharged toward the road surface. This arrangement,however, does not basically solve the problem.

Therefore, the present invention has an object to eliminate theaforementioned problems of prior art.

Another object of the present inventon is to provide exhaust gas outletmeans for an automobile engine in which temperature of exhaust gas canbe decreased to a satisfactory level.

A further object of the present invention is to provide simple andeffective means for decreasing engine exhaust gas temperature.

According to the present invention, the above objects can be achieved byexhaust gas outlet means comprising an engine exhaust pipe having asubstantially flat outlet end with a width smaller than diameter ofunflattened portion of the exhaust pipe and an openended fresh airsuction pipe disposed with a clearance around the outlet end of theexhaust pipe, said suction pipe having a portion of reducedcross-sectional area adjacent to the exhaust pipe outlet end so that asuction throat is defined between the exhaust pipe and the suction pipefor drawing fresh air from one end of the suction pipe and dischargingit with exhaust gas at the other end of the suction pipe.

In an engine having a silencer provided in the exhaust system, the freshair suction pipe may be extended so as to enclose the silencer by theextended portion of the suction pipe. This arrangement is effective toreduce exhaust noise level as well as the exhaust gas temperature.

The above and other objects and features of the present invention willbecome apparent from the following descriptions of preferred embodimentstaking reference to the accompanying drawings, in which:

FIG. 1 is side elevational view of exhaust gas outlet means inaccordance with one embodiment of the present invention;

FIG. 2 is a top plan view of the exhaust gas outlet means shown in FIG.ll;

F103 is an end view of the exhaust gas outlet means shown in FIGS. 1 and2;

FIG. 4 is a vertical sectional view of exhaust gas out let means inaccordance with another embodiment of the present invention;

FIG. 5 is a horizontal sectional view of the exhaust gas outlet meansshown in FIG. 4;

FIG. 6 is an end view of the exhaust gas outlet means shown in FIGS. 4and 5; and

FIG. 7 is a diagram showing exhaust gas temperature changes in varioustypes of exhaust gas outlet means.

Referring now to the drawings, particularly to FIGS. 1 through 3, thereis shown an engine exhaust system including an exhaust pipe 1. As shownin the drawings, the exhaust pipe 1 is flattened in V-shape at itsoutlet end 2. That is, the outlet end 2 tapers from the circular portionof the exhaust pipe 1 into a converging nozzle in one plane and into adiverging nozzle in a transverse plane. The width of the flattenedoutlet end 2 of the ex haust pipe 1 is substantially smaller than thediameter of the unflattened cylindrical portion thereof as clearly shownin FIG. 3. The cross-sectional area of the outlet end 2 is the same asor larger than that of the remaining portion of the exhaust pipe ll.Around the outlet end 2 of the exhaust pipe 1, there is supported anopen ended fresh air suction pipe 3 which is supported with a suitableclearance a with the exhaust pipe I by means of support members 4. Thesuction pipe 3 also has a flattened cross-section as shown in FIG. 3 andreduced in cross-sectional area at the intermediate portion thereof.Thus, a throat portion of reduced crosssectional area is definedadjacent to the outlet end 2 of the exhaust pipe 1. In operation of theengine, therefore, as the exhaust gas is discharged from the outlet end2 of the exhaust pipe 1, a suction pressure is produced in the suctionpipe 3 around the area of reduced cross-section, so that fresh air isdrawn into the pipe 3 from the left end as in FIGS. l and 2, passedtherethrough and discharged from the right end together with the exhaustgas from the exhaust pipe ll. Since the outlet end 2 of the exhaust pipe1 and the suction pipe 3 have flattened cross-sectional shape asdescribed before, the fresh air drawn into the pipe 3 is sufficientlymixed with the exhaust gas from the pipe 1, so that the temperature ofthe exhaust gas is decreased to a satisfactory level.

FIGS. 4 through 6 show another embodiment of the present invention. Inthe drawings, the exhaust gas outlet means includes an exhaust pipe 11which has a flattened outlet end T2. The exhaust pipe ll is supportedunder a vehicle floor by means of a support member 14. In the exhaustpipe lll, there is disposed a silencer 15 which may be of a conventionaltype. Around the end portion of the exhaust pipe 111 and the silencer15, there is disposed a fresh air suction pipe 16 which is supported bymeans of support members 17 on the exhaust pipe 11 with a suitableclearance therewith. Further, the suction pipe 16 is also supported bysupport members 18 on the vehicle floor 13. The suction pipe 16encircles the silencer 15 and flattened around the outlet end 12 of theexhaust pipe 11 as shown in FIG. 6. The suction pipe 16 has an open leftend which defines an air intake port 19 around the exhaust pipe 11.Further, the pipe 16 is provided with a portion 16a of reducedcross-sectional area to define a throat portion around the outlet end 12of the exhaust pipe 11.

In this arrangement, as the exhaust gas is discharged from the exhaustpipe 11, fresh air is introduced from the intake port 19 into thesuction pipe 16, passes around the silencer l and the exhaust pipe 11and is discharged from the suction pipe 16 together with the exhaustgas. This arrangement is effective not only to reduce the exhausttemperature but also to decrease noise level.

FIG. 7 shows exhaust gas temperature in various and modifications can bemade without departing from the scope of the appended claims.

We claim:

1. Exhaust gas outlet means for an internal combustion engine, theoutlet means comprising: an elongated exhaust pipe having apredetermined diameter through a portion of its length, and an outletend whose crosssectional configuration is gradually flattened in a firstplane into a converging nozzle, and whose crosssectional configurationis V-shaped in a second plane transverse to said first plane to define adiverging noz- Zle, the cross-sectional area of said outlet end being atleast equal to that of the exhaust pipe in the said portion of itslength having a predetermined diameter, and an open-ended fresh airsuction pipe disposed around and with a clearance from the exhaust pipeand having a portion of reduced cross-sectional area around the outletend of the exhaust pipe so as to define a suction throat at said outletend.

2. Exhaust gas outlet means in accordance with claim 1 which saidsuction pipe has a flattened crosssectional configuration at saidportion of reduced cross-sectional area.

3. Exhaust gas outlet means in accordance with claim 1 which saidportion of reduced cross-sectional area is formed at the intermediateportion of the suction pipe.

4. Exhaust gas outlet means in accordance with claim 1 in which saidexhaust pipe is provided with a silencer and said suction pipe isextended to encircle said silencer with a clearance thereto.

i l l=

1. Exhaust gas outlet means for an internal combustion engine, theoutlet means comprising: an elongated exhaust pipe having apredetermined diameter through a portion of its length, and an outletend whose cross-sectional configuration is gradually flattened in afirst plane into a converging nozzle, and whose cross-sectionalconfiguration is V-shaped in a second plane transverse to said firstplane to define a diverging nozzle, the cross-sectional area of saidoutlet end being at least equal to that of the exhaust pipe in the saidportion of its length having a predetermined diameter, and an open-endedfresh air suction pipe disposed around and with a clearance from theexhaust pipe and having a portion of reduced cross-sectional area aroundthe outlet end of the exhaust pipe so as to define a suction throat atsaid outlet end.
 2. Exhaust gas outlet means in accordance with claim 1which said suction pipe has a flattened cross-sectional configuration atsaid portion of reduced cross-sectional area.
 3. Exhaust gas outletmeans in accordance with claim 1 which said portion of reducedcross-sectional area is formed at the intermediate portion of thesuction pipe.
 4. Exhaust gas outlet means in accordance with claim 1 inwhich said exhaust pipe is provided with a silencer and said suctionpipe is extended to encircle said silencer with a clearance thereto.